Point Mutations in the Human Vitamin D Receptor Gene Associated with Hypocalcemic Rickets

• Published in: Science (American Association for the Advancement of Science) Vol. 242; no. 4886; pp. 1702 - 1705
• Main Authors: Hughes, Mark R., Malloy, Peter J., Kieback, Dirk G., Kesterson, Robert A., Pike, J. Wesley, Feldman, David, O'Malley, Bert W.
• Format: Journal Article
• Language: English
• Published: Washington, DC The American Association for the Advancement of Science 23.12.1988; American Association for the Advancement of Science
• Subjects: Alfacalcidol; Alleles; Amino Acid Sequence; Animals; Binding Sites; Biological and medical sciences; Calcifediol; Calcitriol - metabolism; Cell Line; Cell Line, Transformed; Cell receptors; Cell structures and functions; Codon; Complementary DNA; Disease; DNA; DNA - genetics; DNA - metabolism; DNA binding proteins; Exons; Female; Fundamental and applied biological sciences. Psychology; Gene Amplification; Genetic aspects; Genetic mutation; Genetics; Genomics; Homozygote; Humans; Hypocalcemia - genetics; Immunoblotting; Introns; Male; Medical research; Molecular and cellular biology; Molecular Sequence Data; Mutagenesis; Mutation; Nucleotides; Receptors; Receptors, Calcitriol; Receptors, Steroid - genetics; Receptors, Steroid - metabolism; Rickets; Rickets - genetics; Skeletal system; Transfection; Vitamin D; Vitamin D metabolism; Vitamin metabolism; Vitamins; Vitamin resistant rickets; Zinc finger; Point mutation; DNA binding protein; Trans acting regulatory factor; Colecalciferol; Biological receptor
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.2849209

Hypocalcemic vitamin D--resistant rickets is a human genetic disease resulting from target organ resistance to the action of 1,25-dihydroxyvitamin D$_{3}$. Two families with affected children homozygous for this autosomal recessive disorder were studied for abnormalities in the intracellular vitamin D receptor (VDR) and its gene. Although the receptor displays normal binding of 1,25-dihydroxyvitamin D$_{3}$ hormone, VDR from affected family members has a decreased affinity for DNA. Genomic DNA isolated from these families was subjected to oligonucleotide-primed DNA amplification, and each of the nine exons encoding the receptor protein was sequenced for a genetic mutation. In each family, a different single nucleotide mutation was found in the DNA binding domain of the protein; one family near the tip of the first zinc finger (Gly$\rightarrow $Asp) and one at the tip of the second zinc finger (Arg$\rightarrow $Gly). The mutant residues were created in vitro by oligonucleotide directed point mutagenesis of wildtype VDR complementary DNA and this cDNA was transfected into COS-1 cells. The produced protein is biochemically indistinguishable from the receptor isolated from patients.